Cytogenetic approaches provide evidence of a conserved diploid number and cytological differences between Proceratophrys species (Anura: Odontophrynidae)

Abstract

Taxonomic and cytogenetic aspects of Proceratophrys have not been thoroughly clarifi ed in the literature; thus, the objective of the present study was to provide unprecedent karyotype data regarding P. schirchi, P. laticeps and P. melanopogon.Additionally, the karyotype of P. boiei (2n = 22) and its ZZ / ZW sex chromosome system was analyzed for different populations of southeastern and southern Brazil. All Proceratophrys species have a diploid number of 2n = 22 chromosomes. In P. schirchi, a strong C-band was found in the long arm in one of the homologues of the pair 8 in female metaphasic cells, denoting that this chromosome pair could represent the heteromorphic sex chromosome in a ZZ / ZW sex system. Despite the conserved number of chromosomes, there are considerable chromosomal differences in P. melanopogon and P. boiei (southern Brazil), strongly differentiating them cytogenetically from other species of the genus. Moreover, with the confi rmation of chromosomal heteromorphism related to sexual differentiation in P. boiei and the possible description of this system in P. schirchi, the Proceratophrys genus can be regarded as an interesting group for evolutionary studies and sex chromosome differentiation in anurans.

Analysis in Proceratophrys boiei genome illuminates the satellite DNA content in a frog from the Brazilian Atlantic forest

“…The use of wild animals, as well as the biological tissues used, were registered in the SisGen–National System for the Management of Genetic Heritage and Associated Traditional Knowledge (registration code: AEF54D5). In addition, we used cytogenetic preparations of P. boiei already available at the Animal Cytogenetics Laboratory in UNESP, Rio Claro, São Paulo, Brazil, from previous studies ( Da Silva et al, 2020 ; Silva et al, 2021 ).…”

“…Surprisingly, the Brazilian frog P. boiei (2n = 22, ZZ♂/ZW♀) has an atypical pattern of heterochromatin distribution, when compared to other anuran amphibians, with large pericentromeric blocks on all chromosomes. In addition, Proceratophrys boiei females have a metacentric W chromosome showing heterochromatin in all chromosomal extension defined by the C-banding technique, e.g., C-positive blocks, being the W chromosome smaller than Z in females ( Ananias et al, 2007 ; Amaro et al, 2012 ; Da Silva et al, 2020 ; Silva et al, 2021 ). So far, it is the only specie of the genus with these atypical chromosomal characteristics, even for amphibians.…”